Wet Process for Recycling Asphalt Shingle in Asphalt Binder

Abstract

A new method is disclosed for recycling waste asphalt shingles in hot mix asphalt, i.e. asphalt pavement construction. Ground asphalt shingles are treated as a binder component instead of as an aggregate component. The recycled asphalt shingles that are blended with virgin binder in a wet process act both as a partial binder replacement and as a binder extender due to the presence of fillers, rubber, and fibers in the processed material.

1 . A process for producing hot mix asphalt from recycled, asphalt-containing roofing shingles; asphalt binder; and aggregate; said process comprising the steps of:
 (a) grinding the shingles to a powder, such that at least 80% by mass of the ground shingles pass a 200 mesh sieve;   (b) heating the asphalt binder to 170 to 180 degrees Celsius;   (c) blending the ground shingles with the heated asphalt binder; wherein the ground shingles are unheated immediately prior to said blending step; wherein no aggregate is included with the ground shingles and asphalt binder during said blending step; and wherein said blending step continues until substantially all asphalt from the ground shingles is melted and blended with asphalt from the asphalt binder; and   (d) mixing the melted blend of ground shingles and asphalt binder from step (c) with aggregate to produce hot mix asphalt.